Short, flexible catheter-cannulas inserted into a blood vessel are employed to a great extent for sampling blood and the intravenous administration of drugs, fluid and blood. They have the advantage over steel needles because they do not easily cause vessel and tissue injuries and haematoma formation when the patient moves. The catheter-cannula is inserted into the blood vessel by a needle slidably mounted within the catheter-cannula, the needle being withdrawn from the catheter-cannula after its insertion into the blood vessel.
Medical personnel have to exercise the utmost of care when using catheter-cannula insertion needles so as not to be accidentally punctured by a contaminated needle resulting in possible exposure to infectious diseases, such as, acquired immune deficiency syndrome (AIDS) or serum hepatitis when inserting a catheter-cannula into the blood vessel of a patient.
In order to provide medical personnel with a safeguard against infectious diseases when manipulating a catheter-cannula insertion needle, the disposable shielded catheter-cannula insertion needle of the present invention has been devised, which comprises, essentially, a catheter-cannula assembly detachably connected to the distal end of a cylindrical housing. A piston assembly is slidably mounted within the housing with the insertion needle being connected to the piston assembly and extending coaxially within the catheter-cannula with the piercing end of the needle protruding from the distal end of the catheter-cannula assembly. A stem, including a cap, is detachably connected to the distal end of the cylindrical housing to provide a cover for the catheter-cannula and insertion needle assembly before use, the stem being insertable into the proximate end of the cylindrical housing and detachably connectable to the piston assembly for drawing the contaminated insertion needle into the cylindrical housing after the catheter-cannula has been inserted into the patient's blood vessel. The cap is connectable to the distal end of the cylindrical housing to completely enclose the contaminated insertion needle within the cylindrical housing, whereby the shielded contaminated insertion needle can be discarded.